Image forming system, image forming method, and program

Abstract

To provide an image forming system that can reduce the amount of recording materials to be discarded.SOLUTION: A control unit, when detecting an abnormality in a conveyance state of a recording material detected by a detection unit, stops conveyance of a recording material to be conveyed subsequent to the recording material, on the upstream of an image forming unit in a recording material conveyance direction, until reading of the position of an image formed on the recording material is completed. When determining that the position of the image read by an image reading unit is normal, the control unit ejects the recording material from a first ejection unit, and when determining that the position of the image read by the image reading unit is abnormal, ejects the recording material from a second ejection unit.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an image forming system, an image forming method, and a program. [Background technology]

[0002] Conventionally, there is known an image forming system in which a reading unit is provided downstream of an image forming unit (see, for example, Patent Document 1). In this image forming system, an image formed on a recording material is read and inspected by the reading unit. The inspection judges whether the output is normal or abnormal by comparing the read image data with correct image data. The inspection also judges whether the output is normal or abnormal for the image forming position on the recording material. Any recording material for which an abnormal output is detected during the inspection is discharged separately from recording materials that have been normally output. Furthermore, any recording material that has been transported to the image forming device and any recording materials for which an abnormal output is detected are also discharged separately from recording materials that have been normally output. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-155814 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above image forming system, the recording material for which abnormal output has been detected and the recording material already transported to the image forming device are all discarded. However, the recording material already transported to the subsequent image forming device includes blank recording material before image formation that is not subject to abnormal output in the inspection, and recording material that is normally output without being affected by the abnormal output of the preceding recording material. In a configuration in which such blank recording material and normally output recording material are all uniformly discarded, a lot of recording material will be wasted.

[0005] In order to solve the above-mentioned problems, the present invention provides an image forming system, an image forming method, and a program that are capable of reducing the amount of discarded recording material. [Means for solving the problem]

[0006] The image forming system of the present invention includes a detection unit disposed upstream of the image forming unit in the recording material conveying direction and detecting the conveying state of the recording material, an image reading unit disposed downstream of the image reading unit in the recording material conveying direction, a first discharge unit and a second discharge unit disposed downstream of the image reading unit in the recording material conveying direction, and a control unit for controlling the conveying of the recording material. When the control unit detects an abnormality in the conveying state of the recording material detected by the detection unit, the control unit stops conveying the recording material conveyed following the recording material upstream of the image forming unit in the recording material conveying direction until reading of the image formed on the recording material is completed. Furthermore, when the control unit determines that the image position of the image read by the image reading unit on the recording material conveyed to the image forming unit is normal, the control unit discharges the recording material from the first discharge unit, and when the control unit determines that the image position of the image read by the image reading unit on the recording material conveyed to the image forming unit is abnormal, the control unit discharges the recording material from the second discharge unit.

[0007] In addition, the image forming method of the present invention detects the conveyance state of the recording material at a detection unit arranged upstream of the image forming unit in the recording material conveyance direction, forms an image on the recording material at the image forming unit, reads the image formed on the recording material at the image reading unit, and discharges the recording material from the first discharge unit or the second discharge unit. If an abnormality is detected in the conveyance state of the recording material detected by the detection unit, conveyance of the recording material conveyed following the recording material is stopped upstream of the image forming unit in the recording material conveyance direction until reading of the image formed on the recording material is completed. If the image position of the image read by the image reading unit on the recording material conveyed to the image forming unit is determined to be normal, the recording material is discharged from the first discharge unit. If the image position of the image read by the image reading unit on the recording material conveyed to the image forming unit is determined to be abnormal, the recording material is discharged from the second discharge unit.

[0008] In addition, the program of the present invention causes a computer to execute the following steps: detecting the recording material transport state by a detection unit arranged upstream of the image forming unit in the recording material transport direction; forming an image on the recording material by the image forming unit; reading the image formed on the recording material by the image reading unit; discharging the recording material from the first discharge unit or the second discharge unit; if an abnormality is detected in the recording material transport state detected by the detection unit, stopping the transport of the recording material transported following the recording material upstream of the image forming unit in the recording material transport direction until reading of the image formed on the recording material is completed; discharging the recording material from the first discharge unit when the image position of the image read by the image reading unit on the recording material transported to the image forming unit is determined to be normal; and discharging the recording material from the second discharge unit when the image position of the image read by the image reading unit on the recording material transported to the image forming unit is determined to be abnormal. Effect of the Invention

[0009] According to the present invention, it is possible to provide an image forming system, an image forming method, and a program that are capable of reducing the amount of discarded recording material. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of an image forming system. [Diagram 2] FIG. 1 is a system block diagram of an image forming system. [Diagram 3] FIG. 2 is a functional block diagram of a control unit of the image forming system. [Figure 4] 11 is a flowchart illustrating an image forming processing method using the image forming system. [Diagram 5] 5 is a flowchart illustrating recording material supply control in the image forming method. [Figure 6] 1A and 1B are diagrams illustrating an example of recording material conveyance in a conventional image forming process. [Figure 7] 5A to 5C are diagrams illustrating an example of recording material conveyance in the image forming process of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, examples of embodiments of the present invention will be described, but the present invention is not limited to the following examples.

[0012] Image forming system FIG. 1 shows a schematic configuration diagram of an image forming system according to the present embodiment. The image forming system 10 shown in FIG. 1 includes a recording material supplying device 100, a recording material conveying device 400, an image forming device 200, an inspection device 500, and a post-processing device 300. In the image forming system 10, recording material S loaded in a recording material supplying device 100 is supplied to an image forming apparatus 200 via a recording material conveying device 400. Then, the recording material S on which an image has been formed by the image forming apparatus 200 is conveyed from the image forming apparatus 200 to an inspection device 500. Furthermore, the recording material S is inspected by the inspection device 500, and then conveyed to a post-processing device 300. Then, the recording material S is subjected to a predetermined post-processing in the post-processing device 300, and then the recording material S is discharged from the image forming system 10.

[0013] [Recording material supply device] The recording material supplying device 100 stores recording materials for image formation. The recording material supplying device 100 supplies a recording material S to an image forming apparatus 200 in response to an image formation job. The recording material supplying device 100 includes a conveying section 50 and a recording material supplying section 70 as a recording material storage section.

[0014] The recording material supplying section 70 is composed of, for example, a plurality of trays arranged inside the recording material supplying device 100. The recording material supplying section 70 is capable of loading a plurality of sheets of recording material S in a stacked state. Fig. 1 illustrates a configuration including four recording material supplying sections 70 arranged vertically. Each recording material supplying section 70 individually stores recording materials of different types and sizes.

[0015] The transport section 50 includes a take-out roller (not shown) that takes out the recording material from each recording material supply section 70, and a plurality of transport rollers 54 for transporting the recording material. The transport rollers 54 are provided along a predetermined recording material transport path. The transport path of the transport section 50 merges the plurality of recording material supply sections 70 into one path. The transport path of the transport section 50 is connected to a recording material transport device 400. The transport section 50 drives the transport rollers 54 to transport the recording material S fed from the recording material supply section 70 to the recording material transport device 400.

[0016] [Recording material transport device] The recording material conveying device 400 includes an entrance 55 through which the recording material S is conveyed into the recording material conveying device 400, a conveying section 51 that conveys the recording material S, an exit 57, and a detection section 71 that detects the characteristics of the recording material S. Note that in the image forming system 10, the detection section 71 may be disposed in the image forming device 200 or the recording material supplying device 100. In this configuration, the recording material conveying device 400 does not need to be provided independently.

[0017] (Transportation section) The recording material conveying device 400 includes a conveying section 51. The conveying section 51 includes a plurality of conveying rollers 54 that convey the recording material S along a conveying path, etc. The conveying section 51 configures a conveying path from an inlet 55, through which the recording material S is conveyed from the recording material supplying device 100 to the recording material conveying device 400, to an outlet 57. The recording material S passes through the outlet 57 and is conveyed from the recording material conveying device 400 to the image forming device 200.

[0018] (Detection unit) The recording material conveying device 400 includes a detection unit 71 in the conveying section 51. The detection unit 71 detects the recording material S being conveyed to the conveying section 51. Note that, in FIG. 1, an example in which two media sensors are arranged as the detection unit 71 is shown. The detection unit 71 detects the conveyance state and recording material characteristics of the recording material S conveyed to the conveying unit 51. The detection unit 71 operates under the control of the control unit 90 (FIG. 2). The detection unit 71 includes various sensors for detecting the conveyance state and recording material characteristics of the recording material S. The detection unit 71 may also include multiple sensors for detecting the conveyance state and recording material characteristics of the recording material S.

[0019] It is preferable that the detection unit 71 detects the conveyance state and recording material characteristics of the recording material S in a state where the conveyance of the recording material S is stopped or in a state where the conveyance of the recording material S is slowed down below the normal conveyance speed for image formation. By detecting the conveyance state and recording material characteristics in a stopped state or a low-speed conveyance state of the recording material S, it is possible to improve the detection accuracy of the recording material characteristics. Furthermore, the detection unit 71 may detect the conveyance state and recording material characteristics in a state where the recording material S is conveyed at the normal conveyance speed for image formation. By detecting the recording material S at the normal conveyance speed, it is possible to detect the conveyance state and recording material characteristics without reducing the productivity of the image formation job.

[0020] The detection unit 71 detects the conveyance state of the conveyed recording material S. The detection unit 71 detects, as the conveyance state of the recording material S, at least one of skewed feeding and one-sided conveyance of the recording material S.

[0021] Furthermore, the detection unit 71 detects the recording material characteristics of the recording material S. The detection unit 71 detects, as the recording material characteristics, the type of recording material Sn (e.g., plain paper, high-quality paper, glossy paper, etc.), size, physical properties of the recording material S, etc. The detection unit 71 detects, as the physical properties of the recording material S, for example, thickness, basis weight, surface properties, stiffness, charge amount, resistance, moisture content, and grain (angle of the fiber direction of the recording material), etc. The detection unit 71 detects at least one of the moisture content, basis weight, thickness, surface condition, stiffness, and resistance.

[0022] The detection unit 71 includes an optical sensor and a weight sensor for detecting the size, weight, and basis weight of the recording material S. The optical sensor has a light receiving element that detects the edge of the recording material S on an inspection table through which the conveyed recording material S passes. Furthermore, the detection unit 71 includes an imaging sensor for detecting the type of recording material S. The imaging sensor includes a light source that irradiates light onto the front surface of the recording material S, a light source that irradiates light from the back surface of the recording material S, and an imaging element that images the front surface of the recording material S. An image of the reflective state when the front surface of the recording material S is irradiated and an image of the transmissive state when the back surface of the recording material S is irradiated are obtained.

[0023] For example, the detection unit 71 includes a contact type rotary encoder to detect the thickness difference of the recording material S. The detection unit 71 includes a roller that holds the recording material S and a push-up material lifting unit that presses the push-up material against the recording material S to detect the stiffness of the recording material S. The detection unit 71 includes detection rollers that pinch the recording material S to detect the resistance.

[0024] The detection unit 71 includes a sensor that detects, as recording material characteristics, electrical characteristics of the recording material S. The detection unit 71 includes a sensor that charges the recording material S in order to detect the electrical resistance value, charge amount, moisture content, and the like of the recording material S. The detection unit 71 has a sensor that detects recording material characteristics through a test that directly contacts the recording material S. The detection unit 71 includes a contact sensor that directly contacts the recording material S to measure the stiffness of the recording material S.

[0025] Furthermore, the detection unit 71 includes a sensor that detects the recording material characteristics without contacting the recording material S. The detection unit 71 detects the recording material characteristics without deforming the recording material due to an external force, thereby suppressing transport problems when the recording material S is transported in the image forming device 200, the image forming unit 240, or the fixing unit 248, and paper jams (so-called jams). For example, the detection unit 71 includes a light irradiation unit that irradiates the recording material S with light of a wavelength that does not absorb moisture and light of a wavelength that absorbs moisture in order to detect the moisture content. The detection unit 71 also includes a light irradiation unit that irradiates the recording material S with light in order to detect the basis weight.

[0026] Furthermore, the detection unit 71 includes a sensor that detects the recording material characteristics without charging the recording material S. The detection unit 71 detects the recording material characteristics without charging the recording material S, thereby suppressing transport defects (jams) caused by the recording material S sticking during transport. Furthermore, the detection unit 71 accurately transfers charge in the electrophotographic process and transfers the toner image from the intermediate transfer belt 246 to the recording material S. The detection unit 71 detects the recording material characteristics in a non-contact and non-charged manner, thereby reducing poor conveyance of the recording material S and improving transfer accuracy in the image forming system 10. In this way, the detection unit 71 suppresses deterioration in the reliability of image formation.

[0027] [Image forming device] The image forming apparatus 200 shown in FIG. 1 includes an operation display unit 220, a scanner 230, an image forming unit 240, a conveying unit 250, and the like.

[0028] The operation display unit 220 is composed of an operation section and a display section. The display unit is configured by a display device such as an LCD (Liquid Crystal Display), and displays various screens according to instructions of a display signal input from the control unit 90 (FIG. 2). The operation unit includes a touch panel formed to cover the display screen of the display unit, and various operation buttons such as numeric buttons and a start button, and outputs an operation signal based on a user's operation to a control unit 90 described later. The operation unit accepts operation instructions from the user.

[0029] The scanner 230 reads an original image and generates image data. The scanner 230 optically scans an original conveyed from an ADF (Auto Document Feeder) onto a contact glass or an original placed on the contact glass. The scanner 230 then forms an image of reflected light, which is emitted from a light source and scanned onto the original, on a light receiving surface of a CCD (Charge Coupled Device) sensor, and reads the original image. The scanner 230 then A / D converts the read image to generate image data.

[0030] The image forming unit 240 forms an image on the recording material S based on image data. The image forming unit 240 includes photoconductor drums 241Y, 241M, 241C, and 241K corresponding to the respective colors of yellow (Y), magenta (M), cyan (C), and black (K), charging units 242Y, 242M, 242C, and 242K, exposure units 243Y, 243M, 243C, and 243K, developing units 244Y, 244M, 244C, and 244K, and primary transfer rollers 245Y, 245M, 245C, and 245K. The image forming unit 240 also includes an intermediate transfer belt 246, a secondary transfer roller 247, and a fixing unit 248.

[0031] The charging sections 242Y, 242M, 242C, and 242K uniformly charge the photoconductor drums 241Y, 241M, 241C, and 241K. The exposure units 243Y, 243M, 243C, and 243K are composed of a laser light source, a polygon mirror, a lens, etc. The exposure units 243Y, 243M, 243C, and 243K scan and expose the surfaces of the photoconductor drums 241Y, 241M, 241C, and 241K with a laser beam based on image data of each color to form an electrostatic latent image. The developing units 244Y, 244M, 244C, and 244K develop the electrostatic latent images on the photoconductor drums 241Y, 241M, 241C, and 241K by attaching toner of each color to the electrostatic latent images.

[0032] The primary transfer rollers 245Y, 245M, 245C, and 245K sequentially transfer (primary transfer) the toner images of each color formed on the photoconductor drums 241Y, 241M, 241C, and 241K onto the intermediate transfer belt 246. As a result, a color toner image is formed on the intermediate transfer belt 246 in which the toner images of four colors are superimposed. The secondary transfer roller 247 transfers the color toner image on the intermediate transfer belt 246 all at once onto one side of the recording material S supplied from the supply tray (secondary transfer). The fixing unit 248 fixes the toner image onto the recording material S by applying heat and pressure to the recording material S by passing the recording material S through a nip portion formed by a fixing roller and a pressure roller.

[0033] The conveying section 250 includes a plurality of conveying rollers 54 and the like that are provided along a predetermined conveying path for conveying the recording material S. The conveying section 250 conveys the recording material along the predetermined conveying path in the image forming apparatus 200 by driving the conveying rollers 54. Then, the recording material S after image formation is conveyed to the post-processing apparatus 300.

[0034] [Inspection equipment] The inspection device 500 has an image reading unit 501 in a housing. The image reading unit 501 reads an image formed on a recording material S. The image reading unit 501 is composed of, for example, a line sensor. The line sensor has optical sensors such as multiple image pickup elements arranged in a direction (width direction) perpendicular to the recording material conveyance direction, and is capable of scanning the entire paper including the image.

[0035] The inspection device 500 may include, for example, a CPU (Central Processing Unit), a system memory, a GPU (Graphics Processing Unit), a GPU memory, a recording unit, and the like, in addition to the image reading unit 501. The CPU and the GPU are processors that perform arithmetic processing. The recording unit stores various control programs and setting data executed by the CPU. The recording unit also stores various information input to the image reading unit 501. Examples of the various information include read image data acquired by the image reading unit and image-processed image data acquired from the control unit 90 of the image forming apparatus 200.

[0036] The CPU reads out various control programs and setting data stored in the recording unit, stores them in the system memory, and executes the programs to inspect the images. The system memory is composed of RAM. At the instruction of the CPU, the GPU stores image data stored in the recording unit or system memory in the GPU memory, and processes the image data, such as image processing and image inspection.

[0037] Furthermore, the inspection device 500 inspects the image (read image data) read by the image reading unit 501, with the CPU and GPU working together. The inspection device 500 inspects the positional deviation of the formed image from the read image data. The inspection device 500 detects at least one of image bias and image inclination as the positional deviation of the formed image. The inspection device 500 also compares the read image data with image data of a correct image (correct image data) under preset inspection conditions to inspect the image. Furthermore, the inspection device 500 may detect defects and deterioration of quality, such as streaks (vertical), streaks (horizontal), other stains (unnecessary toner adhesion, etc.), spotted unevenness, white spots (fireflies), and creases in the recording material (paper creases), from the read image data.

[0038] [Post-processing device] The post-processing device 300 receives the recording material S on which an image has been formed by the image forming device 200. The post-processing device 300 includes a plurality of post-processing units (not shown). For example, the post-processing device 300 includes post-processing units that perform perforation, folding, foil stamping, binding, cutting, stapling, gluing, binding, etc. The post-processing device 300 performs a predetermined post-processing in a post-processing unit designated by a job.

[0039] The post-processing device 300 has a conveying section 52, a conveying section 350, and a conveying section 353. The conveying section 350 and the conveying section 353 are formed by branching off the conveying section 52. Therefore, the post-processing device 300 has a branching section 354 where the conveying section 350 and the conveying section 353 branch off. Moreover, post-processing device 300 includes a first discharge section 351 and a tray 352. Furthermore, post-processing device 300 includes a second discharge section 355 and a tray 356. The first discharge section 351 discharges recording material S conveyed by conveying section 350. The tray 352 stacks recording material S discharged from first discharge section 351. The second discharge section 355 discharges recording material S conveyed by conveying section 353. The tray 356 stacks recording material S discharged from second discharge section 355.

[0040] [System block diagram] Fig. 2 shows a system block diagram of each device constituting the image forming system 10 shown in Fig. 1 described above. As shown in Fig. 2, the image forming system 10 includes a control unit 90, a storage unit 81, a communication unit 82, an operation display unit 220, a scanner 230, an image processing unit 80, a recording material supply unit 70, an image forming unit 240, a detection unit 71, an image reading unit 501, and conveying units 50, 51, 52, and 250. Note that, in the following, a description of the configuration that overlaps with the description of the image forming system 10 shown in Fig. 1 described above will be omitted.

[0041] The control unit 90 includes, for example, a central processing unit (CPU) 91, a read only memory (ROM) 92, and a random access memory (RAM) 93. The control unit 90 is used as an example of a computer that controls the operation of each part of the image forming system 10. The CPU 91 is an example of a calculation unit related to the image forming system 10. The CPU 91 reads out program code of software related to various processes of the image forming system 10 stored in a ROM 92 (an example of a recording medium) and loads the program code into a RAM 93. The CPU 91 then performs centralized control of the operations of the various parts of the image forming system 10 in accordance with the loaded program. Note that instead of the CPU 91, another calculation device such as an MPU (Micro Processing Unit) may be used as the calculation unit. The ROM 92 stores various processing programs for controlling each part of the image forming system 10, parameters and data tables required for executing the programs, various files, and the like. The RAM 93 is configured with a volatile semiconductor memory, and temporarily stores various processing programs read from the ROM 92, input data, output data, parameters, etc., during various processes executed and controlled by the CPU 91.

[0042] The storage unit 81 is an example of a recording medium made of a non-volatile storage, etc. The storage unit 81 stores various processing programs executed by the CPU 91, programs such as an OS, information on the processing functions of the device itself required to execute the programs, image data read by the scanner 230, image data input from a client device (not shown), and various data tables used by the control unit 90 for calculations, etc. The storage unit 81 is composed of, for example, a hard disk drive (HDD), a solid state drive (SSD), an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, etc.

[0043] The communication unit 82 transmits and receives various data to and from an information device (e.g., a client device). The communication unit 82 is composed of a NIC (Network Interface Card), a modem, and the like. The communication unit 82 also transmits and receives various data to and from an information device (e.g., a client device). The communication unit 82 connects the recording material supplying device 100, the image forming device 200, the recording material conveying device 400, the inspection device 500, and the post-processing device 300 to a communication network such as a LAN (Local Area Network) or a WAN (Wide Area Network) to transmit and receive various data.

[0044] The operation display unit 220 functions as a display unit and an operation unit. The display unit displays various operation screens according to a display control signal input from the control unit 90. The operation unit accepts various input operations by the user and outputs operation signals to the control unit 90. The display unit is composed of an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescence) display. The operation unit is composed of a pressure-sensitive or capacitive touch panel or the like on the display unit with transparent electrodes arranged in a lattice pattern.

[0045] The image processing unit 80 is composed of a circuit for analog-to-digital (A / D) conversion processing and a circuit for digital image processing. The image processing unit 80 generates digital image data by performing A / D conversion processing on an analog image signal from the scanner 230. The image processing unit 80 also analyzes a print job acquired from an external information device (e.g., a client device) and rasterizes each page of the document to generate digital image data. Then, the image processing unit 80 performs image processing such as color conversion processing, correction processing (shading correction, etc.) according to initial settings or user settings, and compression processing on the image data as necessary, and outputs the image data after image processing to the image forming unit 240.

[0046] [Function block diagram] 3 shows a functional block diagram of the control unit 90. The control unit 90 includes an image formation control unit 94, a transport control unit 95, a detection control unit 96, and an image inspection control unit 97.

[0047] The image formation control unit 94 controls the image forming operation by the image forming unit 240 of the image forming apparatus 200. The image formation control unit 94 also sets image forming conditions according to the recording material characteristics acquired by the detection control unit 96. For example, the image formation control unit 94 acquires image forming conditions according to the recording material characteristics. The image formation conditions are stored as data in the storage unit 81 or the like. The image formation control unit 94 sets operating conditions for each component of the image forming unit 240. The operating conditions are set based on data acquired from the storage unit 81 or the like. The image formation control unit 94 controls the operation of each component of the image forming unit 240 according to the set operating conditions. The image formation control unit 94 then forms an image on the recording material S based on the image data.

[0048] The transport control unit 95 controls the transport of the recording material S in the image forming system 10. The transport control unit 95 controls the supply of the recording material S from the recording material supply unit 70 to the transport unit 50. The transport control unit 95 controls the transport speed, transport stop, transport restart, etc. of the recording material S in the transport units 50, 51, 52, and 250. Furthermore, the transport control unit 95 controls switching of the transport paths of the transport units 350 and 353 in the post-processing device 300. The transport control unit 95 controls the discharge of the recording material S from the first discharge unit 351 and the discharge of the recording material S from the second discharge unit 355. Furthermore, when the detection control unit 96 detects a transport abnormality of the recording material S, the transport control unit 95 executes a correction process (resist, offset correction, etc.) to correct the transport state of the recording material S. The correction process may be performed only when the detected transport abnormality is within a predetermined range. The predetermined range is, for example, equal to or greater than a first threshold value and equal to or less than a second threshold value, which will be described later.

[0049] The detection control unit 96 detects the conveying state of the recording material S. The detection control unit 96 detects the conveying state of the recording material S based on information acquired by the detection unit 71 of the recording material conveying device 400. For example, the detection control unit 96 detects skewed feed (skew) of the recording material S as the conveying state of the recording material S. The detection control unit 96 extracts a difference in detection timing of the recording material S from two sensors arranged in a direction perpendicular to the recording material conveying direction in the detection unit 71. If the recording material S is conveyed crookedly, the two sensors will have different timings for detecting the leading edge of the recording material S. The detection control unit 96 detects skewed feed (skew) of the recording material S from the difference in detection timing. Furthermore, the detection unit 71 detects one-sided conveyance of the recording material S as the conveyance state of the recording material S. The detection control unit 96 acquires the amount of one-sided conveyance of the recording material S from a line sensor disposed in the detection unit 71 that detects one side edge of the recording material S.

[0050] The detection control unit 96 detects a conveyance abnormality by comparing the acquired conveyance state of the recording material S with a threshold value. The threshold value is stored in the storage unit 81. Furthermore, the detection control unit 96 uses a first threshold and a second threshold as thresholds for detecting a transport abnormality. For example, the detection control unit 96 permits image formation on the recording material S when the transport state of the recording material S is equal to or greater than the first threshold and less than the second threshold. At this time, the transport control unit 95 stops transport of the succeeding recording material S. Furthermore, the detection control unit 96 does not permit image formation on the recording material S when the transport state of the recording material S is equal to or greater than the second threshold. In this case, the transport control unit 95 stops transport of the recording material S upstream of the image forming unit 240.

[0051] The detection control unit 96 also detects the recording material characteristics of the recording material S. The detection control unit 96 detects the recording material characteristics of the recording material S based on the information acquired by the detection unit 71. For example, the detection control unit 96 calculates the moisture content from the difference in the amount of reflected light between a wavelength that does not absorb moisture and a wavelength that absorbs moisture. The detection control unit 96 obtains the basis weight value from the transmittance and reflectance of light using an optical sensor. The detection control unit 96 calculates the thickness of the recording material S from the displacement of the contact rotary encoder. The detection control unit 96 acquires the amount of specular reflection and diffuse reflection of light from the optical sensor and identifies the surface properties. The detection control unit 96 converts the pressure when the contact sensor is pressed into the stiffness of the recording material S. The detection control unit 96 calculates the resistance according to Ohm's law from the current that flows when a high voltage is applied.

[0052] The image inspection control unit 97 instructs the image reading unit 501 to execute image reading. Image reading is performed after an image is formed on the recording material S. The image inspection control unit 97 also acquires data of the read image (read image data) and inspection results from the image reading unit 501. Furthermore, the image inspection control unit 97 may instruct the image reading unit 501 to execute inspection of the read image.

[0053] The image inspection control unit 97 performs image inspection on the read image data. The image inspection control unit 97 performs image inspection under preset inspection conditions. For example, the image inspection control unit 97 performs image inspection by comparing the read image data with image data of a correct image (correct image data). The correct image data is stored in the memory unit 81. Then, the image inspection control unit 97 detects defects and deterioration in quality, such as streaks (vertical), streaks (horizontal), spotted unevenness, white spots (fireflies), and creases in the recording material (paper creases), from the read image data.

[0054] The image inspection control unit 97 also checks the read image data for abnormalities in the position of the formed image. The image inspection control unit 97 detects at least one of image bias and image inclination as abnormalities in the image position.

[0055] The image inspection control unit 97 may change the threshold value for determining whether or not the recording material is conveyed properly according to the inspection accuracy that has been set. The inspection accuracy is changed by the user operating the operation display unit or by an external setting via the communication unit 82.

[0056] [flowchart] Next, an image forming processing method using the above-mentioned image forming system will be described. A flowchart of the image forming processing method is shown in Figures 4 and 5. In the image forming system 10, the CPU 91 of the control unit 90 executes a program stored in the ROM 92 or the storage unit 81 to realize the processing of the flowcharts shown in Figures 4 and 5.

[0057] First, the control unit 90 executes recording material supply control by the transport control unit 95 (step S10). A flowchart of the recording material supply control is shown in Fig. 5. The transport control unit 95 determines whether the last recording material S of the job has been transported from the recording material supply unit 70 of the recording material supplying device 100 to the transport unit 50 (step S101). If the last recording material S has not been transported (NO in step S101), the transport control unit 95 determines whether the next recording material S can be supplied from the position of the preceding recording material S (step S102). When the next recording material S can be supplied (YES in step S102), the conveyance control section 95 supplies the recording material S from the recording material supply section 70 to the conveyance section 50 (step S103). If the last recording material S has been transported (YES in step S101), if the next recording material S cannot be supplied (NO in step S102), or after the recording material S has been supplied to the transport section 50, the process according to this flowchart ends.

[0058] 4, the detection control unit 96 determines whether or not the detection of the conveying state of the preceding recording material S is completed (step S11). If the detection of the conveying state is not completed (NO in step S11), the conveying control unit 95 causes the succeeding recording material S to wait in the recording material supplying device 100 until the detection of the conveying state of the preceding recording material S is completed (step S12).

[0059] When the detection of the conveying state is completed (YES in step S11), or after waiting until the detection of the conveying state of the recording material S is completed, the detection control unit 96 judges whether or not there is an abnormality in the conveying state of the recording material S (step S13). When there is an abnormality in the conveying state of the recording material S (NO in step S13), the conveying control unit 95 judges whether or not the succeeding recording material S is being conveyed to the recording material conveying device 400 (step S14). When the succeeding recording material S is being conveyed to the recording material conveying device 400 (YES in step S14), the conveying control unit 95 causes the succeeding recording material S to wait upstream of the detection unit 71 in the recording material conveying direction (step S15).

[0060] If there is no abnormality in the conveying state of the recording material S (YES in step S13), if the succeeding recording material S is not conveyed to the recording material conveying device 400 (NO in step S14), or after making the succeeding recording material S wait, the conveying control unit conveys the recording material S to the inspection device 500 (step S16). Note that the conveying of the recording material S to the inspection device 500 is performed after the image forming process.

[0061] Next, the image inspection control unit 97 reads the image formed on the recording material S by the image reading unit 501, and judges whether or not there is an abnormality (abnormal output) in the inspection result of the formed image (step S17). If there is an abnormal output (NO in step S17), the detection control unit 96 judges whether or not there is an abnormality in the detection result of the conveying state of the recording material S (step S18). When the detection result of the conveying state of the recording material S does not indicate an abnormality (YES in step S18), the conveying control section 95 discharges the recording material S and the following recording material S to the second discharge section 355 (step S19).

[0062] If the detection result of the conveying state of the recording material S indicates an abnormality (NO in step S18), the conveying control unit 95 discharges the recording material S to the second discharge unit 355 (step S20). Then, the conveying control unit 95 resumes conveying the succeeding recording material S, and the image formation control unit 94 forms the image formed on the recording material S that had the abnormal output, onto the succeeding recording material S (step S21). After the processing of steps S19 and S21, the process returns to the processing of step S10, and the image formation processing continues.

[0063] If there is no abnormal output (YES in step S17), the transport control unit 95 resumes transport of the subsequent recording material S, and the image formation control unit 94 forms the next image on the subsequent recording material S (step S22). Then, the transport control unit 95 discharges the recording material S to the first discharge unit 351 (step S23). Then, the image formation control unit 94 determines whether all image formation for the job has been completed (step S24). If the image formation of the job is not completed (NO in step S24), the process returns to step S10 and continues the image formation process. If the image formation of the job is all completed (YES in step S24), the process according to this flowchart ends.

[0064] In the above-mentioned image forming process, in step S13, the conveying state of the recording material S is detected. Then, in the above-mentioned image forming process, in step S17, the formed image on the recording material S is inspected to detect abnormal output.

[0065] In the image forming process, if the image forming process is performed normally, no abnormality in the conveying state is detected in step S13, and no abnormal output is detected in step S17. Furthermore, if no abnormality in the transport state is detected in step S13, but an abnormal output is detected in step S17, a transport abnormality such as deviation or bending of the recording material S has occurred during transport from detection of the transport state to inspection of the formed image. In other words, it is considered that the transport abnormality has occurred during transport from detection of the transport state to inspection of the formed image. In this case, it is highly likely that a transport abnormality will occur in the subsequent recording material S during transport to inspection of the formed image. For this reason, the control unit 90 discharges not only the recording material S in which an abnormality has been detected in the inspection of image formation, but also the subsequent recording material S to a discharge unit different from that of the recording material S that has been normally output.

[0066] If an abnormality in the conveying state is detected in step S13 but an abnormal output is not detected in step S17, the recording material S has been corrected for bias or bending during conveyance from the detection of the conveying state to the inspection of the formed image, and the conveying abnormality is eliminated. Therefore, the control unit 90 discharges the recording material S for which an abnormality in the conveying state has been detected to the same discharge unit as the recording material S that was normally output.

[0067] If an abnormality in the conveying state is detected in step S13 and an abnormal output is detected in step S17, the abnormality in the conveying state of the recording material S is not resolved from the detection of the conveying state to the inspection of the formed image. Therefore, the recording material S in which an abnormality is detected in the inspection of the image formation is discharged to a different discharge section from that of the normally output recording material S. However, in this case, it cannot be confirmed that a conveying abnormality has occurred during conveying from the detection of the conveying state to the inspection of the formed image. Therefore, the normal image formation process is performed on the subsequent recording material S. Then, if no abnormal output is detected for the subsequent recording material S, the control unit 90 discharges the subsequent recording material S to the same discharge section as the normally output recording material S. If an abnormal output is detected for the subsequent recording material S, the control unit 90 discharges the subsequent recording material S to a different discharge section from that of the normally output recording material S.

[0068] In the above-described processing method, when a transport abnormality is detected, the number of recording materials S discharged to a different discharge portion from the normally output recording materials S is reduced compared to the conventional image forming processing. An example of a conventional image forming process is shown in Fig. 6. In Fig. 6, the first recording material S (hereinafter, the first recording material S1), the second recording material S2, and the third recording material S3 have already been conveyed from the recording material supplying device 100, and the fourth recording material S4, the fifth recording material S5, and the sixth recording material S6 are waiting in the recording material supplying device 100. In this state, if an abnormality in the transport state of the first recording material S1 is detected, the first recording material S1, the second recording material S2, and the third recording material S3 that have already been transported from the recording material supplying device 100 are all determined to be abnormal outputs (transport abnormalities), and are discharged to the second discharge section 355 and discarded. Then, new images are formed on the fourth recording material S4, the fifth recording material S5, and the sixth recording material S6 waiting in the recording material supplying device 100. In Fig. 6, the images formed by the job are represented by "A", "B", and "C". The fourth recording material S4, the fifth recording material S5, and the sixth recording material S6 are processed as normal outputs by the image inspection, and are discharged to the first discharge section 351. 1, when there is only one recording material supplying device 100, the number of recording materials S that are discarded is approximately three. However, when multiple recording material supplying devices 100 are connected, the transport path from the recording material supplying device 100 to the detection unit 71 is long. For this reason, in conventional image forming processes, the number of recording materials S that are discarded increases as the number of connected recording material supplying devices 100 increases.

[0069] Next, an example of the image forming process of the present embodiment is shown in Fig. 7. In Fig. 7, similarly to Fig. 6, the first recording material S1, the second recording material S2, and the third recording material S3 have been conveyed from the recording material supplying device 100, and the fourth recording material S4, the fifth recording material S5, and the sixth recording material S6 are waiting at the recording material supplying device 100. In this state, if an abnormality in the conveying state of the first recording material S1 is detected, the conveying of the second recording material S2 and the third recording material S3 that have already been conveyed from the recording material supplying device 100 is stopped. The second recording material S2 and the third recording material S3 are made to wait, for example, in the recording material conveying device 400. At least the second recording material S2 and the third recording material S3 are made to wait in front of the image forming unit 240.

[0070] If an abnormal output is detected in the inspection of the formed image of the first recording material S1, only the first recording material S1 is discharged to the second discharge section 355 and disposed of. Meanwhile, the second recording material S2 and the third recording material S3 that are kept on standby undergo normal image formation processing. Also, the fourth recording material S4, the fifth recording material S5, and the sixth recording material S6 undergo normal image formation processing. In FIG. 7, the images formed by the job are represented by "A", "B", "C", "D", and "E". As a result, the second recording material S2, the third recording material S3, the fourth recording material S4, the fifth recording material S5, and the sixth recording material S6 are processed as normal outputs by the image inspection and discharged to the first discharge section 351.

[0071] In the image forming process of this embodiment, only the first recording material S1 in which an abnormality in the conveying state is detected is discarded, so the number of recording materials S to be discarded is 1. Furthermore, even if the recording material supplying device 100 is connected, the number of recording materials S to be discarded does not change. Therefore, in the image forming process of this embodiment, when a conveying abnormality is detected, the number of recording materials S discharged to a discharge section different from the recording materials S that are normally output is reduced. In other words, the image forming process described above makes it possible to reduce the amount of recording materials that are wastefully discarded.

[0072] The present invention is not limited to the configurations described in the above-mentioned embodiments, and various modifications and variations are possible without departing from the scope of the present invention. [Explanation of symbols]

[0073] 10 Image forming system, 50, 51, 52, 55, 250, 350, 353 Conveying section, 54 Conveying roller, 57 Exit, 70 Recording material supplying section, 71 Detection section, 80 Image processing section, 81 Memory section, 82 Communication section, 90 Control section, 91 CPU, 92 ROM, 93 RAM, 94 Image forming control section, 95 Conveying control section, 96 Detection control section, 97 Image inspection control section, 100 Recording material supplying device, 200 Image forming apparatus, 220 Operation display section, 230 Scanner, 240 Image forming section, 241Y, 241M, 241C, 241K Photoconductor drum, 242Y, 242M, 242C, 242K Charging section, 243Y, 243M, 243C, 243K Exposure unit, 244Y, 244M, 244C, 244K Development unit, 245Y, 245M, 245C, 245K Primary transfer roller, 246 Intermediate transfer belt, 247 Secondary transfer roller, 248 Fixing unit, 300 Post-processing device, 351 First discharge unit, 352, 356 Tray, 354 Branch unit, 355 Second discharge unit, 400 Recording material conveying device, 500 Inspection device, 501 Image reading unit

Claims

1. a detection unit disposed upstream of the image forming unit in a recording material conveying direction, the detection unit detecting a conveying state of the recording material; an image reading unit that reads an image formed on the recording material; a first discharge unit and a second discharge unit disposed downstream of the image reading unit in the recording material transport direction; a control unit for controlling the conveyance of the recording material, The control unit is when an abnormality in the conveying state of the recording material is detected by the detection unit, conveyance of the recording material conveyed following the recording material is stopped upstream of the image forming unit in the recording material conveying direction until reading of the image formed on the recording material is completed; when it is determined that the image position of the image read by the image reading unit on the recording material conveyed to the image forming unit is normal, the recording material is discharged from the first discharge unit; When it is determined that the image position of the image read by the image reading section on the recording material conveyed to the image forming section is abnormal, the recording material is discharged from the second discharge section. Image forming system.

2. The control unit is when it is determined that the image position of the image read by the image reading unit is abnormal, forming an image identical to the image formed on the recording material on a recording material conveyed following the recording material; When it is determined that the image position of the image read by the image reading unit is normal, a second image is formed on a recording material conveyed following the recording material. The image forming system according to claim 1 .

3. The control unit detects at least one of skewed feeding and offset conveyance of the recording material as the detection of the conveyance state of the recording material. The image forming system according to claim 1 .

4. The control unit detects a conveying state of the recording material as well as physical property values ​​of the recording material. The image forming system according to claim 1 .

5. The control unit acquires at least one of a moisture content, a basis weight, a paper thickness, a surface property, a stiffness, and a resistance as a physical property value of the recording material. The image forming system according to claim 4 .

6. The control unit changes a threshold value for determining an abnormality in the conveyance state of the recording material in accordance with a set inspection accuracy. The image forming system according to claim 1 .

7. the control unit determines an abnormality in a conveying state of the recording material by using a first threshold value and a second threshold value; when the conveying state of the recording material is equal to or greater than the first threshold value and less than the second threshold value, a recording material conveyed following the recording material is stopped to form an image on the recording material; When the conveyance state of the recording material is equal to or greater than a second threshold value, conveyance of the recording material is stopped upstream of the image forming unit. The image forming system according to claim 1 .

8. A detection unit disposed upstream of the image forming unit in the recording material conveying direction detects the conveying state of the recording material, An image is formed on the recording material in an image forming section; An image reading unit reads an image formed on the recording material; The image forming method includes discharging the recording material from a first discharging section or a second discharging section, when an abnormality in the conveying state of the recording material is detected by the detection unit, conveyance of the recording material conveyed following the recording material is stopped upstream of the image forming unit in the recording material conveying direction until reading of the image formed on the recording material is completed; when it is determined that the image position of the image read by the image reading unit is normal for the recording material conveyed to the image forming unit, the recording material is discharged from the first discharge unit; When it is determined that the image position of the image read by the image reading section is abnormal for the recording material conveyed to the image forming section, the recording material is discharged from the second discharge section. Image forming method.

9. a step of detecting a conveyance state of the recording material by a detection unit disposed upstream of the image forming unit in a recording material conveyance direction; forming an image on the recording material in an image forming section; a step of reading an image formed on the recording material by an image reading unit; discharging the recording material from a first discharge portion or a second discharge portion; when an abnormality in the conveying state of the recording material is detected by the detection unit, stopping conveyance of a recording material conveyed following the recording material upstream of the image forming unit in the recording material conveying direction until reading of the image formed on the recording material is completed; a step of discharging the recording material from the first discharge section when it is determined that an image position of the image read by the image reading section is normal for the recording material conveyed to the image forming section; a step of discharging the recording material from the second discharge section when it is determined that an image position of the image read by the image reading section is abnormal for the recording material conveyed to the image forming section. program.

Images